[plt-scheme] Slideshow subitem #:bullet (redefinition)

Hello,

In Slideshow I am trying to redefine the bullet showed by a "subitem"
by setting it with the #:bullet option but I can't get it changed as
the slide keeps on displaying the default o-bullet.

Probably I am missing something.

This is my test code:

#lang slideshow

(slide #:title "Test Item/subitem bullets.."
       (item #:bullet (tt "x")
              "This redefines the bullet as 'x'.")

       (subitem #:bullet (tt "*")
              "This 'should' (I think) re-define the o-bullet as '*'
but it doesn't ..")
       )

Thank you in advance for any suggestion.

Ale><